Review round 1 on PR #170 found two more handlers with the #169 class of bug (verified by execution): - brain_update resolved its caller path with resolveWithin, a lexical containment check: any brain file could be superseded (classification.yaml, raw/, sessions/), and a final symlink was written through. UpdateNote now resolves like brain_edit (notes.Resolve, ScopeNotes: knowledge/ and wiki/ .md notes), and reads and rewrites through brainfs (ReadRegular, WriteRegular). - session_log joined the caller's session_id onto the sessions dir and opened it O_CREATE|O_APPEND: an id with path segments created or appended a .jsonl file anywhere the pod could write. The id must now be a plain name (^[A-Za-z0-9_][A-Za-z0-9._-]{0,127}$, which every live session file matches), and the open adds O_NOFOLLOW|O_NONBLOCK. Read checks the id too. - Tunnel tests: the .txt case now names an existing file (it failed on "missing" before), the symlink test adds an in-brain target, and the FIFO comment no longer claims the handle check is the only guard. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>